Analysis of a Compressive Event in the Magnetopause

Abstract

AbstractUnder the quiet solar wind condition, the dayside magnetopause is at about 10RE from the center of the Earth. But under the extreme solar wind condition, such as large southward component of Interplanetary Magnetic Field (Bz) and (or) large solar wind dynamic pressure (DP), the magnetopause will be compressed even inside the geosynchronous orbit. We analyze the magnetic storm on April 11, 2001 to investigate how the compression of the magnetopause would influence the magnetic field in the geospace and on the ground when it was strongly compressed. We choose Shue (1998) model to predict the configuration of the magnetopause. By comparison of the calculation with the observation of the GOES10 satellite on the geosynchronous orbit, we find that under the extreme solar wind condition, the magnetopause does move inside the geosynchronous orbit. Shue (1998) model can predict it approximately well; some faults may be due to its inaccurate position. The location and intensity of the CF‐current on the magnetopause are almost same as the results from the model of the ideal discontinuous surface. For large magnetic storms, the compression of the magnetopause can cause obvious magnetic field disturbances on the ground at the middle and low latitudes. In the event mentioned above, this contribution can be larger than 50nT, which is almost 1/6 of the main phase. So, the compression of the magnetopause may generate considerable error in Dst index.